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X86: Use the new forced folding mechanism for the SAHF and LAHF instructions.

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This commit is contained in:
Gabe Black 2009-08-05 03:04:17 -07:00
parent 664d50b439
commit ef3896d851
2 changed files with 4 additions and 26 deletions
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10
src/arch/x86/isa/decoder/one_byte_opcodes.isa
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@ -330,14 +330,8 @@
//The 64 bit versions of both of these should be illegal only
//if CPUID says it isn't supported. For now, we'll just assume
//that it's supported.
0x6: decode MODE_SUBMODE {
0x0: SAHF_64();
default: SAHF();
}
0x7: decode MODE_SUBMODE {
0x0: LAHF_64();
default: LAHF();
}
0x6: SAHF();
0x7: LAHF();
}
0x14: decode OPCODE_OP_BOTTOM3 {
0x0: MOV(rAb, Ob);

20
src/arch/x86/isa/insts/general_purpose/flags/load_and_store.py
View file

@ -55,26 +55,10 @@
microcode = '''
def macroop SAHF {
# This will fold to ah since this never executes in 64 bit mode.
ruflags rsp, dataSize=1
};
# This is allows the instruction to write to ah in 64 bit mode.
def macroop SAHF_64 {
ruflags t1
slli t1, t1, 8
mov t1, t1, rax, dataSize=1
mov rax, rax, t1, dataSize=2
ruflags ah, dataSize=1
};
def macroop LAHF {
# This will fold to ah since this never executes in 64 bit mode.
wruflags rsp, t0, dataSize=1
};
# This is allows the instruction to read from ah in 64 bit mode.
def macroop LAHF_64 {
srli t1, rax, 8, dataSize=2
wruflags t1, t0, dataSize=1
wruflags ah, t0, dataSize=1
};
'''